This invention is directed to solar heaters and more particularly to a solar system for generating electrical power.
The conventional approaches to obtaining power from sunlight in solar thermal power systems are to concentrate sunlight onto a light absorbing surface to produce a hot zone in which either water is boiled to produce steam or in which a heat transfer medium such as liquid sodium is heated and used to carry heat to a central reservoir where the accumulated heat is used to operate a steam boiler. These approaches have the following difficulties: In the steam boiler approach, either many small power generating systems must be used if large amounts of energy are to be produced, or steam must be collected over large distances. If good efficiency is to be maintained, the steam must be at high pressure and moderately high temperature, with the result that large costs are encountered in the form of high pressure tubing. Also, the daily heating and cooling of the long pipes mean that daily extension and contraction of the piping system is encountered, increasing the likelihood of mechanical failure. The latter problem is even greater with the use of a high temperature, heat transfer medium, and additional problems are encountered due to energy loss in the transfer lines due to heat conduction to the atmosphere. Extreme measures, such as vacuum jacketing, are resorted to in order to control this problem.